Pre-filled syringes that are filled with a selected dosage of a medicament are well known devices for administering the medicament to a patient. Safety devices for covering a needle of a pre-filled syringe before and after use are also well known. Typically, a needle shield of the safety device is either manually moved or moved by the action of a relaxing spring to surround the needle.
A different type of safety devices known in the state of the art solve the object of providing needle safety by arranging the pre-filled syringe movable relative to a body, wherein the pre-filled syringe is retracted into the body after the injection.
Amongst others, injection devices known in the state of arts comprise a safety device and a pre-filled syringe that is retained within the safety device, so that an injection can be safely performed.
Document FR 2 884 722 discloses an injection device comprising a syringe, an outer body, a spring-loaded inner sleeve, an outer and an inner needle shield. The spring-loaded inner sleeve is connected to a plunger of the syringe so that a medicament contained in the syringe may be expelled upon release of the spring. Initially, the inner sleeve is retained against the biasing force of the spring in by retaining means and the outer needle shield surrounds an injection needle. The retaining means are released upon translation of the outer needle shield into a proximal position uncovering the injection needle. The released inner sleeve urges the plunger in the distal direction to expel the medicament through the injection needle. After the drug is delivered, the spring further urges the inner needle shield distally to cover the injection needle to provide needle safety.
FR 2 884 722 A 1 discloses an injection support device for an injection device comprising at least one body. at least one needle and at least one piston seal housed in said body. further comprising at least:                a sheath provided with at least one support surface.        a sleeve movable relative to said sleeve and having at least one gripping area. said sleeve having coupling means for linking said gripping area to said piston seal or to said body for axial translation from an initial position to an insertion position.        
WO 2007/047200 A 1 discloses a pharmaceutical delivery apparatus including a housing. a syringe assembly. and a needle cap. The syringe assembly is plungeable relative to the housing from a first position. at which its needle tip is disposed within the housing. to a second position. at which its needle tip projects from the housing beyond the proximal end for insertion into an injection site. A base of the needle cap is exposed at the housing proximal end to be manually grippable for cap removal. A needle cap stem is upstanding from the base and sized and configured to insert through an opening is the housing proximal end to cover the needle tip when the syringe assembly is disposed in the first position. The needle cap base further includes a plurality of distally projecting cams located radially outward of the stem. The cams are fittable within slots in the housing proximal end when the cap is fully mounted to the apparatus.